Method for performing map matching in user terminal

ABSTRACT

A method for performing a map matching in a user terminal includes determining a space where the user terminal is located using positioning data that is measured at predetermined time intervals, searching one or more links that are located within a range of a preset distance from the space as a candidate link, selecting one of the candidate links which best meets at least one suitability criterion of at least two suitability criteria including distance suitability and space suitability, and carrying out the map matching with respect to the selected one candidate link.

RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2013-0068468, filed on Jun. 14, 2013, which is hereby incorporated byreference as if fully set forth herein.

FIELD OF THE INVENTION

The present invention relates to a method for performing a map matchingin a user terminal, and more particularly, to a method for performing amap matching to match onto a map a position of a user terminal measuredusing a positioning device.

BACKGROUND OF THE INVENTION

Navigation systems are generally mounted on vehicles and are used asterminal devices for vehicles that help drivers travel and reach his/herdestination with ease by displaying a road map for the drivers orsearching a route to the destination.

An automotive navigation system being currently widely used is anapparatus that identifies a current position of a car or a user in realtime by calculating signals received from satellites using a GlobalPositioning System (referred to as ‘GPS’, hereinafter), convertsrelevant data in a database, which contains map information and trafficinformation built previously, corresponding to the current position intoimage/voice information in association with the database, and displaysthe converted image/voice.

The automotive navigation system includes a GPS receiver to calculate acurrent position of a car. The automotive navigation system obtainsinformation on current speed, time and position of the car through theuse of the GPS receiver and provides a user with navigation informationbased on such information.

However, when the current position using GPS signals is calculated,there normally occurs an error of tens of meters because ofcharacteristics of the GPS signals. Therefore, when such an error isused to calculate the current position on a map, the current positionmay be erroneously displayed on a point out of a road, on a rooftop of abuilding or the like.

In order to resolve such a drawback, a typical automotive navigationsystem employs a map matching method when calculating a position of acar. According to the map matching method, a current position iscompared to road data under an assumption that the car is driving on aroad. When the difference between the current position and the road datafalls within a predetermined range, the automotive navigation systemdetermines that the car is driving along the relevant road and forciblycorrects the current position to a point on a road nearest to thecurrent position.

Korean Laid-Open Patent Publication No. 10-2010-0067578 suggests anapparatus and method for map matching of a moving object. It discloses amap matching method to correct a position coordinate of a moving objectsuch as a vehicle moving on a road, wherein a position of the movingobject is corrected into a point on the road when coordinate data of theroad does not exist on a map data and thus it is not easy to make aconventional map matching.

Japanese Laid-Open Patent Publication No. 2002-318121 discloses anavigation system, which is capable of determining a current position ofa moving object when the moving object moves into an indoor facility.First, the navigation system determines a current position of the movingobject by performing a map matching on an output data from a stand-alonesensor and an output data from a GPS apparatus using a map data whilethe moving object is moving. Thereafter, when it is detected that thecurrent position of the moving object is located within an indoorfacility, the navigation system performs a map matching on the outputdata from the stand-alone sensor using a map data to determine thecurrent position of the moving object.

Generally, when a user terminal such as the automotive navigation systemreceives a positioning data or measures its current position, a positionof a user is displayed by performing a map matching on the positioningdata to network data (for example, such as a node or link) nearest tothe position of the user. When performing the map matching, however,even in the case that the user is located indoors, especially, at aspecific indoor space, the user terminal renders a positioning result tomap-match to nearest network data. Accordingly, it is not possible toprecisely reflect a real position of the user who is actually locatedindoors on the map.

SUMMARY OF THE INVENTION

In view of the above, the present invention provides a method tocorrectly reflect a real position of a user terminal on a map.

Further, the present invention provides a method to selectively performa space matching or a network matching depending on a user selection.

Further, the present invention provides a method to perform a mapmatching to which a history of a map matching that has been performedalready is reflected.

As set forth above, the embodiment of the present invention performs amap matching on a position of a user terminal that is measured by aposition device to display the position on a map, whereby the positionof a user terminal can be displayed on the map as compared to aconventional network-based map matching.

Further, it is possible to remove a temporary error issue caused by apositioning device by accumulating the positions of the user terminalfor some period of time and determining a position of the user terminalat a current time using the accumulated positions of the user terminalsfor displaying it.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of embodiments given inconjunction with the accompanying drawings, in which:

FIG. 1 is a view explaining a network map matching and a space mapmatching in accordance with an embodiment of the present invention;

FIG. 2 illustrates a situation where there is a need to perform a spacemap matching;

FIG. 3 is a flowchart schematically illustrating a method of performinga map matching in a user terminal in accordance with an embodiment ofthe present invention;

FIG. 4 is a flowchart explaining in detail a process performed in BlockS302 shown in FIG. 3 in accordance with an embodiment of the presentinvention;

FIGS. 5A and 5B are respectively an exemplary diagram and a tableexplaining a simple decision in accordance with an embodiment of thepresent invention;

FIG. 6 is a diagram illustrating a PIP (Point In Polygon) algorithm usedto determine which space a positioning of a user terminal is located inin accordance with an embodiment of the present invention;

FIGS. 7A and 7B are respectively an exemplary diagram and a tableillustrating an example how to make a section decision in a the userterminal;

FIG. 8 is a diagram illustrating an example how to search candidatespaces in performing a space map matching;

FIG. 9 is a diagram illustrating an example how to search candidatelinks in performing a network map matching;

FIG. 10 is a diagram illustrating another example how to searchcandidate links in performing a network map matching;

FIG. 11 is a diagram illustrating distance suitability; and

FIG. 12 is a diagram illustrating connection suitability.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The above described and additional aspects of the present invention willbe further apparent from the preferred embodiments explained withreference to accompanying drawings. Hereinafter, these embodiments ofthe present invention will be described in detail so that they can bereadily apprehended implemented by those skilled in the art.

In the entire specification, when a portion “comprises” a constituent,it means that the portion does not exclude another constituent butfurther comprises other constituent if not described otherwise. Further,terms such as “unit”, “apparatus”, “module” and “block” mean a unit toprocess at least one of functions or operations, and they can beembodied by hardware or software or a combination of hardware andsoftware.

An indoor map matching is a map matching that needs to comprehensivelyconsider a space and a network due to the addition of a concept of aspace to an existing network map matching. The term of “space” usedherein means specific spatial extent divided by semantic usage such as astore, a dining room, a sensor coverage area, and so on.

A map matching in associated with the present invention is classifiedinto a space map matching and a network map matching. The space mapmatching means to match a real position of a user terminal that ismeasured by a positioning device to a specific space area such as astore, a dining room, a part of corridor, whereas the network mapmatching means to match a position of a user terminal that is measuredby the positioning device to a link or a node. The link or node refersto a point or position at which the position of the user terminal is setas a starting point in order to search a route to a destination, whenthe user terminal requests the route search. That is, the route searchis started from not a real position of the measured user terminal butany one of the links or nodes.

FIG. 1 is a view explaining a network map matching and a space mapmatching in accordance with an embodiment of the present invention.Hereinafter, the network map matching and the space map matching inaccordance with an embodiment of the present invention will be describedin detail with reference to FIG. 1. Referring to FIG. 1, there is showna plurality of spaces including SPACE 1, SPACE 2, SPACE 3, . . . , andSPACE 8, and SPACE 9 (which is represented by a corridor in FIG. 1)adjacent to each space. A space may be one space physically and also onespace logically. That is, as shown in FIG. 1, while a set of SPACE1 toSPACE3 may be one space physically, each space may be one of threespaces which are logically divided from one physical space. Similarly,the corridor may be integrally one space or may be separated intodesired number of spaces.

Each space includes an entry node intended to enter the space. Thespaces SPACE 1 to SPACE 8 each include an entry node to enter eachspace.

Additionally, the corridor has a link. The link is a moving route of auser to guide the user along a searched route. For an outdoorenvironment, the link may be a road on which a vehicle moves, and for anindoor environment, the link may be a corridor through which a useraccesses an entry node. Of course, a node may be placed on the linkbecause one link consists of two nodes as illustrated in FIG. 1.Referring to FIG. 1, a node may be formed at a crossing point of linksand an entry point of each space.

According to a related art, when a position of a user terminal ismeasured by a positioning device, the position of the user terminal ismatched to a link. Whereas, the present invention is proposed to performa space map matching as well as a network map matching in order todetermine a correct position of the user terminal.

Hereinafter, the network map matching will be described first. Asdescribed above, the user terminal performs the network map matchingwhen a route search is requested from the outside.

As illustrated in FIG. 1, a position of a user terminal measured by apositioning device is indicated by a triangle. When a task requested tothe user terminal is a route search, the position of the user terminalis matched to an entry node constituting a link or a space. For example,in SPACE1, it can be shown that a position of a user terminal is matchedto a link that is formed at an entry node or a link formed in acorridor. In each of SPACE3 and SPACE6, it can also be shown that aposition of the user terminal is matched to an entry node within eachspace. In addition, when a position of the user terminal is at any onepoint in the corridor, it can be shown that the position of the userterminal is matched to a link formed in the corridor. As such, inaccordance with the embodiment, the user terminal performs the networkmap matching on the position of the user terminal when the requestedtask is the route search. Hereinafter, the space map matching will bedescribed.

The space map matching means to match a real position of the userterminal, which is measured, within a specific space. In other words,the space map matching refers to a process of matching the just measuredposition of the user terminal to a position within a particular spacethat is determined, without moving the measured position to a positionon a network. For example, in FIG. 1, the position of the user terminalmeasured by a positioning device is indicated by a triangle, and theposition of the user terminal is marked at a real position that isindicated by the triangle. FIG. 2 illustrates a situation where there isa need to perform the space map matching in accordance with anembodiment of the present invention. Referring to FIG. 2, if it does notconsider a space concept, even though a user is currently located at aSHOP 1, the position of the user would be map-matched to a link formedin a corridor through a network map matching. Moreover, if the user islocated at a space where the SHOP 1 and a corridor are separated by awall, the user may experience an unacceptable map matching result.Therefore, the concept of a space is a method to match positioning datato be within a specific area of an indoor space and is efficient todetermine whether which space a user or a user terminal is reallylocated in.

FIG. 3 is a flowchart illustrating a method of performing a map matchingin a user terminal, in accordance with an embodiment of the presentinvention. Hereinafter, a process of performing a map matching in a userterminal will be described as follows.

In block S300, a user terminal receives positioning data. That is, theuser terminal measures a position of the user terminal using apositioning device. Of course, the user terminal may receive informationabout its position via a separate positioning device outside the userterminal or an external server having a positioning functionality. Theuser terminal may measure its own position by way of communicating withan NFC (Near Field Communication) module or through the use of a QR(Quick Response) code. In addition, the user terminal may also measureits own position by way of utilizing various technologies such as aWiFi, Zigbee, Bluetooth and the like.

In block S302, the user terminal determines whether which space theposition of the user terminal is located in. That is, the user terminalperforms the space map matching on the position of the user terminalbased on the positioning data and determines a space where the userterminal is located and spaces to which the user terminal may be movablein the future. Such a process carried out in block S302 will bedescribed with reference to FIG. 4 later.

In block S304, the user terminal determines whether a network mapmatching has ever performed or not based on the positioning data. If thenetwork map matching has not yet been made, the method advances to blockS306 to perform an initial map matching based on the positioning data.However, if the network map matching has already been made, the methodgoes to block S310 to perform an estimation map matching based on thepositioning data and a map matching result that has been madepreviously. The details for the initial map matching and the estimationmap matching will be mentioned later. The initial map matching may bemade in sequence as follows:

determining a space->extracting candidate links->performing suitabilitydecision on the candidate links->carrying out effectiveness test.

A procedure of determining a space has already been performed in blockS302 and a procedure of extracting candidate links will be explainedfrom block S306 as follows.

In block S306, the user terminal searches one or more candidate links.That is, the user terminal searches one or more candidate links thatwill be subjected to the map matching.

Hereinafter, a process of extracting a first candidate link to bematched will be described with reference to FIG. 9. In the initial mapmatching process, a distance criterion is established to search thecandidate links around the positioning data. While the embodimentdescribes to search the candidate links within a range of 10 m (on adistance basis) based on the positioning data, it is not limitedthereto. For example, the distance criterion may differ with a settingfrom a user or a variety of conditions.

The suitability decision and the final link extraction will be processedas follows.

In block S308, the user terminal carries out a suitability decision withrespect to the candidate links. That is, the user terminal determineswhether the candidate links are suitable and then selects a candidatelink which has the highest suitability.

First, a suitability decision is made with respect to the respectivecandidate links. That is, distance suitability and space suitability arecalculated with respect to each of the candidate links, a total score ofthe respective calculated suitability is compared with a reference scoreto determine whether each of the candidate links is to be registered orabolished. A final link is selected as a link having a largestsuitability among the candidate links that has been registered.

During the suitability decision, when there is no link within a presetradius defined on the basis of the positioning data, the user terminaldetermines that this map matching is failed and then retries to performthe initial map matching. As an example, the preset radius may be about20 m.

Next, the sequence of the estimation map matching is as follows:

determining a space->performing an initial effectivenesstest->extracting candidate links->performing suitability decision on thecandidate links to yield a map matching result->performing aneffectiveness test.

The estimation map matching is a process capable of improving aneffectiveness of the map matching by simultaneously reflecting a pastmap-matching record and positioning data that is currently received.However, when the positioning data that is received and the past mapmatching result are not effective in the course of the estimation mapmatching, the past map-matching record may be reset and then the initialthe map matching will be resumed.

In block S310, the user terminal performs an initial effectiveness test.In the initial effectiveness test, a previous positioning data iscompared to a current positioning data. When an amount of change inpositions of the current positioning data relative to the previouspositioning data is above a preset range, the initial effectiveness testis reset and a process returns to the initial map matching. As anexample, when an amount of change in positions is more than or equal to20 m, the initial effectiveness test is reset and the initial mapmatching is recommenced.

In block S312, the user terminal searches one or more candidate links.That is, the user terminal searches one or more candidate links thatwill be subjected to the estimation map matching. The user terminalsearches a new candidate link based on the candidate links that beensearched in the previous map matching. That is, the user terminalsearches a new candidate link from the candidate links that beensearched in the previous map matching. Among the previous candidatelinks, the user terminal remains one or more candidate links whosedistance from the current position is below a preset distance remain asa candidate link and registers the candidate links satisfying acondition that a connecting link connected to a previous candidate linkis less than or equal to a preset distance from the current position.

Thereafter, the user terminal performs the suitability decision andyields the map matching result.

In block S314, the user terminal carries out a suitability decision withrespect to the candidate links. That is the user terminal calculates ascore of the suitability for the respective candidate links inaccordance with a criterion for the suitability decision and thenselects one candidate link which has the highest suitability. That is,the user terminal decides the suitability with respect to the respectivecandidate links that are newly registered and selects one candidate linkthat has a highest score of the suitability.

The user terminal makes a decision of link suitability with respect tothe respect candidate links that have been newly searched. Morespecifically, the user terminal calculates distance suitability, passagesuitability, route suitability, connecting suitability, spacesuitability with respect to the respect candidate links. The userterminal compares a total score of the respective suitability for eachcandidate link with a preset score of a reference suitability todetermine whether to remain or abolish the candidate link. In thisconnection, the user terminal discards any one of candidate links thatare duplicated. The user terminal selects one candidate link as a finalcandidate link, which has a largest suitability from among the candidatelinks that remain the registration. It is understood that a ratio bywhich the space suitability occupies the total suitability score maydiffer with the presence or absence of the route suitability.

In block S316, the user terminal stores the selected candidate link orupdates a previously selected candidate link with a newly selectedcandidate link.

In block S318, the user terminal carries out an effectiveness test. Thatis, the user terminal performs the effectiveness test on the map-matchedresult. When determining that the map-matched result is not effective,the user terminal initializes this map matching and resumes the initialmap matching. By way of an example, when a candidate link fails to passthe space suitability and has a distance more than 10 m away from aprevious positioning data and when a candidate link succeeds to pass thespace suitability, but has a distance more than 20 m away from aprevious positioning data, the user terminal determines that thecandidate link is not effective, that is, the candidate link cannotfinally pass the effectiveness test.

When the effectiveness test result indicates validity, the method goesto block S322, and otherwise, when the effectiveness test resultinvalidity, the method flows to block S320 where a content that has beenstored in block S316 is cleared.

In block S322, the user terminal outputs a map matching result. That is,the user terminal generates a map matching result in which the positionof the user terminal is map-matched to a link or a space, which has thehighest suitability. Map matching result values may include spaceinformation that is determined, map-matched link information,map-matched location, and a projected distance from positioning data toa link when matching on the link. Further, the map matching location mayinclude a map-matching location within a space before performing thenetwork map matching and a map matching location on a link afterperforming the network map matching.

FIG. 4 is a flowchart explaining in detail a process performed in BlockS302 shown in FIG. 3 in accordance with an embodiment of the presentinvention. Hereinafter, the process of performing a map matching in theuser terminal will be described in detail with reference with FIG. 4.

In block S400, the user terminal receives positioning data. That is, theuser terminal measures its own position using a positioning device. Forexample, the user terminal may measure its own position by way ofcommunicating with an NFC module or through the use of a QR (QuickResponse) code. In addition, the user terminal may also measure its ownposition by way of utilizing various technologies such as a WiFi,Zigbee, Bluetooth and the like.

In block S402, the user terminal performs a simple decision/sectiondecision. First, the simple decision will be described as follows.

The simple decision is to detect a position of the user terminal on atime unit basis with the positioning data, which is input, as areference. FIGS. 5A and 5B show respectively an exemplary diagram and atable explaining a simple determination in accordance with an embodimentof the present invention.

Referring to FIGS. 5A and 5B, considering in respect of the positioningdata that is input, it is determined that the user terminal is locatedin a SPACE 6; however, only at time T4 on the table, it is determinedthat the user terminal is located at a SPACE 1. Nonetheless, if the userterminal has kept staying in the SPACE 6 actually, the determinationmade at time T4 may be wrong. Thus, in order to take account such anerror, a section decision may be conducted on a basis of the simpledetermination in accordance with the embodiment of the presentinvention.

FIG. 6 is a diagram illustrating a PIP (Point In Polygon) algorithm usedto determine which space the user terminal is located in.

In FIG. 6, a half line, which starts with one point, is created to passthrough a polygon. After that, it is determined whether the point islocated within the polygon from the number of intersections between thehalf line and the polygon.

When the number of intersections is an odd number, it is determined thatthe point is located within the polygon, and otherwise when the numberof intersections is an even number, it is determined that the point islocated outside the polygon.

With the foregoing in mind, referring to FIG. 6, for a first point CASE1, since the number of intersections is three, which is an odd number;therefore, the point is determined to be within the polygon. For asecond point CASE 2, since the number of intersections is four, which isan even number; therefore, the point is determined to be out of thepolygon.

Now, the section decision will be described as follows. The sectiondecision is a method to carry out the simple decision on a section basisin order to make up for a matching error which may occur in the simpledecision.

FIGS. 7A and 7B are respectively a diagram and a table showing anexample making a section decision in the user terminal. The sectiondecision ties each specific number of simple decision results in onesection to yield the greatest value (or the highest frequency) in eachsection as a final result. Referring to FIGS. 7A and 7B, for example,when a set of three positioning data is grouped into one section, theposition of the user terminal will be determined to be stayed in a SPACE6 at time T4. That is, a space where the user terminal is located attime T4 may maintain the same space where the user terminal has beenlocated at time T3. Of course, the position of the user terminal in thecorresponding space may differ actually. Both the simple decision andthe section decision may consider an accuracy, accumulated directioninformation, etc. as well as the positioning data.

In block S404, the user terminal searches one or more candidate spaces,and if needed, stores the candidate spaces.

After searching the candidate spaces where it is expected that the userterminal is located through the section decision approach, a spaceeffectiveness test is conducted for each of the candidate spaces.

As illustrated in FIG. 8, when it is determined that the position of theuser terminal is located in a SPACE 6 through the use of the sectiondecision, a space where the user terminal is expected to be moved may bea SPACE 2 and a SPACE 1, which have a connectivity with a space wherethe user terminal is currently located, inclusive of the SPACE 6.

A novel method for deriving one or more candidate spaces is proposed byan embodiment of the present invention and is described as follows:

1. Detecting a space where a user is located through the use of simple &section decisions based on positioning data,

2. Spawning network data starting from a representative node of thespace detected by the step 1;

3. Carrying out a PIP (Point in Polygon) test of an end node of the linkthat is spawned (on a basis of a spawning direction);

4. Searching a space including the end node of the link that is spawnedthrough the PIP test and storing the searched space if the correspondingspace is different from the space where the user is located; andstopping the spawning in the direction of the search.

5. Carrying out the step 4 on a connecting link direction basis. But, ifan attribute of the end node of the link considering the spawningdirection has “a door node”, the spawning is performed to search for anext connecting link without passing through the PIP test.

In block S406, the user terminal checks whether the space map matchinghas ever been performed. When it is checked that none space map matchinghas been made, the user terminal performs the initial map matching basedon the positioning data, and otherwise, when it is checked that thespace map matching has already been made, the user terminal performs theestimation map matching based on the positioning data and a previous mapmatching result.

In block S408, the user terminal checks a space effectiveness test. Ifthere is an existing result for deriving a candidate space, the userterminal may check whether a currently searched space is an effectivespace base on the existing result. That is, a candidate space that issearched on a basis of the connectivity of a currently matched spacebecomes a subject to be checked. Therefore, another space except thecandidate space, which is determined as a result of the search, cannotpass through the space effectiveness test.

In block S414, the user terminal resets this space map matching when itis determined that the matched space is not effective.

In block S416, the user terminal yields a space map matching result.Values of the space map matching result may include map-matched spaceinformation such as an ID, map-matched coordinates in the map-matchedspace, and the like. Further, the map matching location may include amap-matching location within a space before performing the network mapmatching and a map matching location on a link after performing thenetwork map matching.

Hereinafter, individual suitability will be described separately indetail.

FIG. 10 is a diagram illustrating an example of searching candidatelinks; and FIG. 11 is a diagram illustrating the distance suitability inaccordance with an embodiment of the present invention.

The distance suitability considers a distance between the positioningdata and the respective candidate links. By way of example, a largestradius for the distance suitability is set within a range of 20 m. Ascore of the distance suitability may be calculated in consideration ofa ratio deviated from a link with reference to a maximum allowableradius and a largest score of the distance suitability.

The passage suitability is calculated by comparing passage codes of alink and a traveling direction of the link.

The route suitability considers whether positioning data presents on aroute that is searched if the searched route exist.

The connecting suitability considers whether a previous matching linkhas a connecting link. FIG. 12 is a diagram expressing the connectingsuitability.

The space suitability considers whether a space is available for moving.

While the present invention has been shown and described with respect tothe preferred embodiments, the present invention is not necessarilylimited thereto. It will be easily appreciated by those skilled in theart that various substitutions, changes and modifications may be madewithin a scope without departing from the technical idea of theinvention.

What is claimed is:
 1. A method for performing a map matching in a userterminal, the method comprising: determining a space where the userterminal is located using positioning data that is measured atpredetermined time intervals; searching one or more links that arelocated within a range of a preset distance from the space as acandidate link; selecting one of the candidate links which best meets atleast one suitability criterion of at least two suitability criteriaincluding distance suitability and space suitability; and carrying outthe map matching with respect to the selected one candidate link.
 2. Themethod of claim 1, wherein said determining a space where the userterminal is located comprises: determining whether the user terminalmoves to another space from the space, which is measured at thepredetermined time intervals, where the user terminal is located;determining whether the user terminal moves from another space where theuser terminal is located to the space where the user terminal has beenlocated previously within the predetermined time intervals; and when itis determined that the user terminal moves, accumulating at least threepositioning data measured at predetermined time interval to determinewhether which space the user terminal is located in.
 3. The method ofclaim 1, wherein said determining a space where the user terminal islocated comprises: accumulating at least three positioning data measuredat predetermined time interval to determine whether which space the userterminal is located in.
 4. The method of claim 2, further comprising:determining whether there is a record which has determined a space wherethe user terminal is located; and when it is determined that there isthe record, determining whether the space that is determined that theuser terminal is located has a connectivity with the space where theuser terminal has been located previously.
 5. The method of claim 1,wherein said selecting one of the candidate links comprises: determiningwhether a distance between a position of the user terminal, which isdetermined from a previously measured positioning data, and a positionof the user terminal, which is determined from a currently measuredpositioning data, falls within a range of a preset distance; and whenthe distance falls within the range of the preset distance, selectingeither the candidate links which are derived through the use of thepreviously measured positioning data or connecting links of thecandidate links as the candidate link, wherein the selected candidatelinks or the selected connecting links meet a preset condition.
 6. Themethod of claim 5, wherein the selected candidate links or the selectedconnecting links meet a preset condition comprises: the candidate linkswhich are located within a range of preset distance from a position thatis determined from currently measured positioning data or connectinglinks of the candidate links.
 7. The method of claim 1, wherein thesuitability criterion comprises at least one of: distance suitability todetermine a distance from the position of the user terminal to acandidate link; a space suitability to determine whether the position ofthe user terminal is movable to a candidate link; a route suitability todetermine whether the position of the user terminal, which is measuredusing the positioning data, is located on a route; a passage suitabilityto define passage codes of a link and a traveling direction of the link;and a connection suitability to determine whether a previous candidatelink has a candidate link.
 8. The method of claim 1, further comprising:after said performing a map matching, displaying a map matching result,wherein the map matching result comprises information about the spacethat has been determined and information about the link that has beenmatched.
 9. The method of claim 8, wherein the map matching resultcomprises at least one of: a matching location within the space that hasbeen determined; a location of the matched link; and a distance betweenthe matched location within the space and a location of the matchedlink.
 10. A method for performing a map matching in a user terminal, themethod comprising: performing a space map matching to determine a spacewhere the user terminal is located using positioning data that ismeasured at predetermined time intervals; and performing a network mapmatching to match a position of the user terminal to network data usingpositioning data that is measured after performing the space mapmatching.